tor-rtmock: Docs updates (and an API fix)
I'm not sure the README.md
(crate-level) docs is the right place for this?
Anyway, I hope this shows how I think things can be used.
It's up to the test author to decide which things go into subtasks and which things into the main task.
These kind of tests would be a bit simpler (fewer oneshots) if our tasks could return values and be awaited. That would be a possible extension to MockExecutor
but I'm not doing it now.